EP0463435B1 - Verwendung von Magnesiumtitanat-Pulver - Google Patents

Verwendung von Magnesiumtitanat-Pulver Download PDF

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Publication number
EP0463435B1
EP0463435B1 EP91109400A EP91109400A EP0463435B1 EP 0463435 B1 EP0463435 B1 EP 0463435B1 EP 91109400 A EP91109400 A EP 91109400A EP 91109400 A EP91109400 A EP 91109400A EP 0463435 B1 EP0463435 B1 EP 0463435B1
Authority
EP
European Patent Office
Prior art keywords
magnesium
titanate
raw materials
raw material
ceramic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Revoked
Application number
EP91109400A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0463435A1 (de
Inventor
Bernhard Dr. Freudenberg
Johannes Dipl.-Ing. Seyer
Gerhard Dr. Auer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
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First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=6408845&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0463435(B1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Bayer AG filed Critical Bayer AG
Publication of EP0463435A1 publication Critical patent/EP0463435A1/de
Application granted granted Critical
Publication of EP0463435B1 publication Critical patent/EP0463435B1/de
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/465—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on alkaline earth metal titanates
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/46—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates
    • C04B35/462—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates
    • C04B35/478—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on titanium oxides or titanates based on titanates based on aluminium titanates

Definitions

  • the present invention relates to the use of a magnesium-containing ceramic raw material with improved processing properties in aqueous slip casting.
  • Magnesium compounds are often added to the ceramic raw material mixture in order to improve the sintering behavior and the properties of the finished sintered molding.
  • the aluminum oxide ceramic contains magnesium compounds to promote the compaction during the sintering.
  • the silicon nitride ceramic also contains magnesium compounds to enable the sealing sintering.
  • magnesium compounds are added to the aluminum titanate ceramic in order to improve the thermal stability at high temperatures.
  • magnesium oxide and magnesium spinel are used as the magnesium source.
  • EP-B 36 462 lists magnesium oxide, magnesium carbonate and magnesium hydroxide as possible raw material components.
  • magnesium silicate is preferred as the backfill component, in particular the natural silicate sepiolite (4 MgO x 6 SiO2 x 7 H2O).
  • Talc is also preferably incorporated as a magnesium raw material in accordance with US Pat. No. 2,776,896.
  • column 7, line 3 ff the use of MgO x 2 TiO2 as an additive is mentioned, among others, without going into the shaping process. Advantages and disadvantages compared to other magnesium sources are not described.
  • MgO-containing offsets are often incorporated into alcohols or hydrocarbons as dispersing agents (see, for example, SG WHITEWAY and others "Slip Casting Magnesia” in Ceramic Bulletin 40 (1961) pp. 432-438), which causes considerable effort in practice.
  • SiO2-containing raw material mixtures there is a strong tendency towards heterocoagulation, which manifests itself as a thickening of the slip.
  • EP-A-31 29 23 also describes a MgTiO3-containing composition for the production of low-burning capacitors, in particular multilayer capacitors. These are produced either by the process of film casting or by the process of thick film technology. In both cases, the suspension, consisting of a fine ceramic powder and a thin or viscous medium and auxiliary materials, is applied to a non-absorbent surface. The suspension solidifies through evaporation of the solvent. This technology allows the production of thin-walled, especially flat components. Only organic media are used as the suspension medium Substances disclose, knowing well, that the dispersion of alkaline earth compounds in the aqueous system would cause problems.
  • This process is therefore neither a slip casting process nor is it carried out in an aqueous medium.
  • Natural raw materials also lead to considerable problems with ingestion.
  • Talc is inherently hydrophobic.
  • Natural sepiolite with its high alkali content releases a large part of it as electrolytes into the dispersing agent, which leads to thickening of the slip.
  • the object of this invention was to provide a magnesium-containing raw material in aqueous slip casting which does not have the disadvantages of the prior art described.
  • This invention thus relates to the use of magnesium titanate powder as a magnesium source in ceramic slip casting raw material mixtures.
  • magnesium titanate allows the production of a slurry with a higher solids content and reduced structural viscosity.
  • the magnesium titanate powder according to the invention is preferably one or more from the group MgTiO3, Mg2TiO4 and / or MgTi2O5. Another advantage of using magnesium titanate powder is the high reactivity in ceramic firing, see also the example below.
  • the natural raw materials contain, in particular, alkali and calcium impurities, which lead to reduced resistance to decay in the case of aluminum titanate ceramics.
  • the amount of magnesium titanate used is preferably 0.05 to 50 wt .-%, calculated as MgTiO3 and based on the total raw material mixture.
  • the raw material mixtures are aluminum titanate raw material mixtures. Particularly good results are achieved if the raw material mixture contains more than 30% by weight of aluminum titanate or aluminum titanate mixed crystals after sintering.
  • Mg-containing raw materials were incorporated into an aluminum titanate batch.
  • the batch contained a total of 56.7 wt .-% Al2O3, 40.4 wt .-% TiO2, 2.6 wt .-% SiO2 and 0.3 wt .-% MgO.
  • MgTiO3 AC 5555, Bayer
  • MgO 2000A, Chemag
  • MgAl2O4 Chemag
  • sepiolite type S, Mandt
  • Table I shows the phase composition after a reaction time of 10 h at 1300 ° C. in air determined by X-ray diffraction.
  • MgAl2O4 proves to be relatively inert.
  • MgTiO3 is the most reactive compound.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Ceramic Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Producing Shaped Articles From Materials (AREA)
EP91109400A 1990-06-22 1991-06-08 Verwendung von Magnesiumtitanat-Pulver Revoked EP0463435B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4019861 1990-06-22
DE4019861A DE4019861A1 (de) 1990-06-22 1990-06-22 Verwendung von magnesiumtitanat-pulver

Publications (2)

Publication Number Publication Date
EP0463435A1 EP0463435A1 (de) 1992-01-02
EP0463435B1 true EP0463435B1 (de) 1994-04-06

Family

ID=6408845

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91109400A Revoked EP0463435B1 (de) 1990-06-22 1991-06-08 Verwendung von Magnesiumtitanat-Pulver

Country Status (3)

Country Link
EP (1) EP0463435B1 (enExample)
JP (1) JPH04228425A (enExample)
DE (2) DE4019861A1 (enExample)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4897163B2 (ja) * 2001-09-19 2012-03-14 太平洋セメント株式会社 アルミナ質焼結体の製造方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2776896A (en) * 1952-10-22 1957-01-08 Cambridge Tile Mfg Company Ceramic composition having thermal shock resistance
DE2750290C3 (de) * 1977-11-10 1987-07-09 Hoechst CeramTec AG, 8672 Selb Verwendung eines gebrannten keramischen Formkörpers zur Herstellung von Metall-Keramik-Verbundkörpern
EP0128956B1 (en) * 1982-12-22 1990-07-11 Tam Ceramics Inc. Low firing ceramic dielectric for temperature compensating capacitors
US4845062A (en) * 1987-10-19 1989-07-04 E. I. Du Pont De Nemours And Company Low-firing dielectric composition

Also Published As

Publication number Publication date
DE4019861C2 (enExample) 1993-06-09
DE4019861A1 (de) 1992-01-09
DE59101312D1 (de) 1994-05-11
EP0463435A1 (de) 1992-01-02
JPH04228425A (ja) 1992-08-18

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